Just a codicil ...
Unfortunately, "delete" now has varied and unspecified meanings in Aperture, and is no longer a useful word. I suggest (the OP 😉 ) stop using the word "delete" and replace it, in writing but especially in thinking, with the specific action desired. Once the action is specified, the appropriate command can be found and used.
Some of the different actions we associate with "delete" are (when the selection is an Image or Images):
- remove from Album (Books, Light Tables, etc. are all specialized Albums)
- move from Project to Aperture Trash
- remove from all Albums and move from Project to Aperture Trash
- move from Aperture Trash to System Trash
- remove from System Trash
I use Projects as long-term storage containers and Albums as "output" containers. I remove Images from Albums when I no longer need them for the output I am working on. I move them from their Project to the Aperture Trash when I no longer wish to keep them. I empty the Aperture Trash after every work session. As a general rule: I work in Projects when I am administering the collection of Images in my Library; I work in Albums when I am preparing Images for publication, and publishing them. ("Publish" meaning "use outside Aperture".)
Imho, the program designers would do well to more fully address the multiple non-identical understanding of "delete" in Aperture.
Message was edited by: Kirby Krieger -- replaced text clipped when first posted.